In the UK, supermarket chain Tesco is being pounded right now in social media channels because it’s refusing to honor an erroneous online advertisement offering new iPads for about $65. The offer went viral, and now the backlash is viral, too. How Tesco responds will tell the tale. I’d recommend a sincere apology, a few well-phrased jokes poking fun at itself — and an offer to make it up to those who still want to buy an iPad from them.